There's a Limit light in the AS355F-1 I'm flying right now. Don't have the manual here, so I'm not sure if it's a mod or if it's original.
We flew an intentional jackstall on the Gazelle. It takes quite a bit of effort to put yourself into that condition. I agree that if it could be designed out of the system without consequence then it should, but it's not as if there's a very large accessible and easy to use "DO NOT TOUCH THIS" button in the cockpit.
Like many things helicopter, it does require the pilot to understand and be aware in able to prevent and if required, recover.